Adjustable electric contact



F. H. LORKING.

ADJUSTABLE ELECTRIC CONTACT. Armcmou mm DEC.5, I919.

1,347,391. Patented July 20,1920.

AWE/V708 Z2 wax /5921,40 aw/m:

ATTOAAEK)".

UNITED STATES PATENT OFFICE.

ADJUSTABLE ELECTRIC CONTACT.-

Specification of Letters Patent. 7 Patented J l 20 1920 'Application -filed December 5, 1919. Serial No. 342,634.

- To all whom it may concern:

Be it known that 1, FnANors IIOWARD humans, a subject of the King of Great Britain and Ireland, residing'at No. 10 Davenport Terrace, l/Vayville, State of South Australia, Commonwealth of Australia, have invented certain new and useful Improved Adjustable Electric Contacts, of which the following is a specification.

This invention comprises a contact for electrical work which grips an adjusting nut and even when the wire-holding nuts are slackened off for adjustment or other purpose, remains locked to the insulating block and is capable of a micrometer adjustment thereon. It is especially suitable for circuit breakers, polechangers and circuit controllers used in si nal engineering or other work where comparatively light currents are used.

According to my invention the heel of the contact is bifurcated and the two branches thus formed are bent at right angles to the stem of the contact but parallel to one another and having between them a space sufficient to enable a nut to be pushed therein, the spring of the two branches holding the nut locked, and the two branches being perforated to slide upon the screwthreaded end of a stud which is rigidlysecured in and projects from the insulating block, the said nut being adjustable upon the said stud.

Referrlng to the accompanying drawings.

Figure l is a side view illustrating a single contact constructed according to my invention.

Fig. 2 shows the contact proper.

Fig. 3 is a side view illustrating a somewhat diiferent form of my contact and application thereof, two contacts being shown.

Fig. 4 is a plan view of one of the contacts shown in Fig. 3.

The heel of my improved contact is bifurcated and the two branches 1 and 2 are bent at right angles to the stem 3 of the contact. They are perforated to take the stud 4. which projects from the insulating block 5 and are spaced at such distance apart as to enable a nut 6 to be forced between them when assembling the contact on the insulatin block 5. j

The insulating block 5 has formed in its under or upper side according towhioh type of contact is used a shallow groove 7 in which the stem 3 of the contact slides and is prevented from moving sidewlse at any time during adjustment.

lVhen the contact is in position in the groove 7 on the under or the upper side of the insulating block it remains locked in posltion without any further nuts or other fastening being added for this purpose. The contact cannot come out of the groove even when being adjusted. This feature prevents the contact from falling or slipping to one side and short circuiting other contacts while an adjustment is being made. The two branches 1 and 2 and the groove 7 form a brace and when the lead wire 9 is locked in position the contact is quite rigid.

In the construction shown in Figs. 3 and 4 the perforated branch 1 is extended and bent again at right angles to fit into a groove 7 across the top of the insulating block. The lead wire 9 is attached by lock nuts 10 upon the stud 4: against one of the branches of the contact. Adjustments are made by using the spanner at right angles to the plane of adjacent contacts; this is the simplest movement and there'is small chance of short circuiting other contacts with the spanner.

The novelty of this device lies in the combination of the compactness, the accurate adjustment, and the secure locking of the contact. Instead of a stud and nut projecting at right angles to the contact, the stud 4 according to my invention projects from the block 5 parallel to the contact. The adjustment is absolutely accurate because the contact must follow the inward and outward movement of the locked nut 6 between the branches 1 and 2.

What I claim as my invention is 1. An adjustable contact having at its heel two spaced and perforated branches, an insulating block, a threaded stud-projecting from the insulating block and eX- tending through the perforations of the branches, and a nut on the stud betweenthe said branches.

2. An adjustable contact, comprising a contact having at one end of its stem bifurcations, said bifurcations being perforated and extending at right angles to the stem, an insulating block, a threaded stem projecting from the insulating block parallel with the stem of the contact and extending through the perforations of the bifurcations of the stem, and a nut on the stud between the said bifurcations.

3. An adjustable contact, comprisin a contact having a bifurcated end ext-en mg at right angles therefrom, the members of In testimony that I claim the foregoing said end being provided with alined openas my invention I have signed my name, in 10 ings a threaded stud' adapted-to be secured the pre's'ene'e' of we subscribing Witnesses,

to a support of insulating IIl zLt61iiL1 S2Lid-Stud this 23d da of October 1919.

extending through the openings of the mem- I FHA CIS HOWARD LORKING. bers, a nut on the stud between the said Witnesses: 7 members, and lock nuts on the e'i'idof the ARTHUR Gonn CoLLIsoN. stud. KATHLEEN M CoLLIsoN. 

